Mod 9 - Networking Basics
Notes
- Network Topologies
- Bus
- Devices are connected via a single cable
- Simple and cost effective, but insecure and may have performance issues
- Ring
- Devices are connected on a loop where data travels one direction
- Simple, but not scalable
- Reduced data collisions, but still prone to performance issues
- Star
- Devices all connect to a central hub
- Scalable, simple troubleshooting
- Central device is a point of failure
- Mesh
- Devices each connect to multiple other devices, creating a web or “mesh”
- Expensive + complex setup, not scalable
- Very reliable, fault tolerant, good bandwidth
- A hybrid star / mesh topology is most common today
- Network Devices
- Servers: provide resources, data, programs, or services to other devices
- Hubs: a simple network device that sends incoming data to all attached devices
- Switches: connects multiple devices and direct packets to their destination device
- Routers: connect networks to each other and direct packets to their destination network
- Bridges: connect network segments to make them act as a singular network
- Access Points: allow wireless devices to connect to a wired network
- Types of Networks
- Networks are categorized based on geographic range, number of devices, and how they connect
- LAN (Local Area Network): covers a small area such as a home or school
- WLAN (Wireless Local Area Network): LAN that uses WiFi instead of cables
- WAN (Wide Area Network): covers large geographical areas such as cities or countries, connecting multiple LANs
- MAN (Metropolitan Area Network): covers a city or small campus (in-between LAN and WAN)
- PAN (Personal Area Network): a very small network consisting of connections between one person’s devices
- Network Addressing
- IP Address
- Parts of an IP Address
- Network ID
- Beginning of address
- Anywhere from 8 to 30 bits
- Host ID
- Whatever is left over from Net ID
- Subnet Mask:
- Defines how many bits are in the Net ID
- IP Address Example
- Binary IP address:
- 10000001101010100001001011011100
- Translated to dotted decimal:
- Subnet Mask is /24
- First 24 bits are Network ID
- Net ID: 129.170.18
- Host ID: 220
- MAC Address
- Unique to every network adapter
- Domain Name System (DNS)
- A hierarchical, distributed system that translates website names into IP addresses, like a phonebook for the internet.
- Example:
- Open Systems Interconnection (OSI) Model
- Network protocol framework that uses 7 layers
- The layers define the different stages that data goes through to travel from one device to another over a network
- OSI Model Layers:
- Physical Layer (1)
- Wires and signals
- carries data
- Data Link Layer (2)
- Getting data across the wires
- MAC addresses
- Network Layer (3)
- Finding the best route
- IP addresses and routers
- Transport Layer (4)
- Keeping data in order
- TCP and UDP
- Session Layer (5)
- Managing connections
- Keeping you connected
- Presentation Layer (6)
- Translation Data
- convert data into a format your device understands
- Application Layer (7)
- Network Security Toolkit: Wireshark
- A popular tool for “capturing” network traffic. (also called sniffing
- Captures all traffic to and from local host
- Will parse packet “headers” and display the info in an organized way
- Can filter results to show specific sessions, protocols, hosts, etc.
Vocabulary & Key Terms
Network
- A network is a group of interconnected devices that communicate and exchange data.
- Networks can have different topologies, devices, and sizes/types.
Slides
Mod 9 - Networking Basics (slides)